ER will provide a showcase for several marquee Emmy Award-winning and nominated guest stars this fall with a roster that includes Andre Braugher, John Mahoney and a return appearance of Oscar and Emmy winner Sally Field, who reprises the series role that won her an Emmy.

In addition, John Stamos will become a series regular when he resumes his previous guest-starring role from last year as Tony Gates, a savvy paramedic and medical student. The Emmy-winning drama series will also feature other prominent guest stars, including Paula Malcomson.

Over a span of six episodes beginning in the season's fifth episode, Braugher will play a carpenter who enters the emergency room with a seemingly simple cough. But due to heavy patient congestion, he suffers a stroke while waiting despite the attempts of Dr. Kovac (Goran Visnjic) and his life eventually falls apart as a result of his paralysis. Earlier, Braugher starred on NBC's "Homicide" as a tough police murder detective and won an Emmy as Outstanding Lead Actor in a Drama Series.

In an offbeat casting, Mahoney will portray a performing drag queen who wants to assume legal authority for his dying partner's medical care. The two-time Oscar-winning Field returns to play the bipolar and problematic mother of Doctor Abby Lockhart (Maura Tierney) in the second episode. Malcomson will appear in a multi-episode arc as the widow of Gates' (Stamos) deceased best friend and war buddy, a single mother trying to navigate the everyday hardships of child-rearing. She depends on Gates in many ways to provide a father figure for her daughter as well as companionship for them both -- and that includes becoming occasional lovers.